There are still two preseason games to go, and many more practices to be evaluated, but the Bills' quarterback competition took a decided turn Friday night at Ralph Wilson Stadium.

Veteran Kevin Kolb was given the start against the Minnesota Vikings and though he left the game at halftime with Buffalo ahead 13-3, he did not distinguish himself in any way.

Rookie EJ Manuel took over at the start of the third quarter, led an impressive TD drive on his first possession, and the Bills hung on to earn a 20-16 victory over the Vikings.

"He got off to the same start EJ did in the last game," coach Doug Marrone said of Kolb. "It's tough when it's the first time you come into it. Kevin did a nice job at the end, making sure that we scored."

Kolb clearly looked rusty in his first game action of the summer. He completed 13 of 21 passes for 111 yards, but almost every completion came on a short route or dumpoff, and the incompletions were almost all his fault. One errant pass intended for Marquise Goodwin was tipped by Xavier Rhodes and intercepted by Jamarca Sanford at the Bills' 31.

"I was disappointed with myself in the first quarter, but it's been a long time since I've seen live action, it's been a long time since I've been on the field, so I'll just keep getting better and keep pushing," said Kolb.

His only two productive series came as the half was winding down and all of Minnesota's starting defenders were on the bench. On the first, he completed 7 of 8 passes for 49 yards, but a holding penalty on Colin Brown forced the Bills to settle for a 39-yard Dustin Hopkins field goal 1:12 before halftime.

Buffalo forced a Minnesota punt, Kolb took possession with 38 seconds left, and he hit Marcus Easley for 21 yards and Robert Woods for 22 on back-to-back plays to set up Hopkins' 35-yard field goal as the clock ran out.

"It obviously started slow, it took a little while for the game to come to me there, but I was happy with the way it finished," he said. "We got into a little bit of a groove. Things are a little different on a game field than a practice field. I thought we finished well, had a couple good drives there with a few minutes left."

Manuel was greeted by a loud roar when he trotted onto the field to start the third quarter, and he responded with a 14-play, 80-yard drive, capping it with with a four-yard touchdown pass to wide-open Brad Smith.

Manuel completed all six of his passes for 43 yards, two coming on third down as he hit Easley for 12 yards and Chris Hogan for eight to keep the drive alive.

On his next two possessions, Manuel was pinned inside his own 3-yard-line. The first was a three-and-out, but he moved Buffalo out to the Minnesota 46 on the second before a sack on the final play of the third quarter forced a punt, and ended his night. He finished 10 of 12 for 92 yards.

Third-stringer Jeff Tuel played the fourth quarter.

While the quarterback competition was front and center on the minds of the Kids Day crowd that numbered in the 40,000 range, the Buffalo defense had the most eye-catching performance.

The Bills came after Minnesota quarterbacks Christian Ponder and Matt Cassel and made them look terrible. They were a combined 9 of 20 for 82 yards and were sacked three times, twice by Jerry Hughes and once by Marcell Dareus.

"Early on our defense played really well, made some things happen," said Marrone. "Defensively, I think we've tried to establish an identity from day one. We still have a lot to improve on, but again, I like that type of effort. I was very happy with the defense."

The Vikings took a 3-0 lead on a 36-yard first-quarter field goal by Blair Walsh, but then it was the Buffalo defense that gave the Bills the lead for good. Minnesota center Joe Berger sailed a shotgun snap over Cassel's head midway through the second quarter, and linebacker Jamie Blatnick fell on it in the end zone for a touchdown.

After Manuel's TD pass to Smith, the Vikings found their groove on offense and scored a pair of fourth-quarter touchdowns to pull within 20-16 with 4:36 left in the game.

"Our goal coming into the preseason was to win the games and our players did that," said Marrone. "We've still got a long way to go and a lot to work on."